Why not? If they're only making minimal money from Bitcoin sales just keep it and see how much it's worth in a few months or later in the year. If the price is going to gradually rise they'd be silly to spend it.
I agree with your logic, but most businesses I've spoken to are far more concerned about running their business than speculating on a currency. Definitely it depends on the sector, but for example, retail & entertainment certainly are not currently interested.
I'm sure those businesses wont, but if you own a bar or a cafe and put a Bitcoin sign in your window I guarantee you will get a bit of interest and extra customers. You might only sell a few items in Bitcoin a month, but that's the experiment and hopefully their custom in BTC will grow along with Bitcoin adoption.